The incidence of gestational diabetes, characterized as glucose intolerance with onset during pregnancy, is increasing. Diet, physical activity, and obesity are modifiable risk factors that have been implicated in gestational diabetes. Concurrently, there has been concern regarding the increase in obesity, motivating interest in identifying environmental determinants of obesity that might impact individual behavior, including features of the neighborhood in which one lives. One neighborhood feature that might impact the risk of obesity and that of gestational diabetes is the availability of healthy foods. Another neighborhood feature is ethnic concentration. South Asian, Latin American, African, and Caribbean women are at an increased risk of gestational diabetes, especially those who are foreign-born. It has been suggested that this increased risk found in immigrant women might in part be due to change in diet and lifestyle upon immigration. Thus, it is likely that for immigrant women, living outside of ethnic enclaves might increase their risk of gestational diabetes by exposing them to greater changes in diet and lifestyle, while experiencing decreased social and instrumental support. Using linked New York City hospital discharge, birth certificate, commercial food, and census data, this study will be the first ever to examine the association between neighborhood characteristics and the risk of gestational diabetes. The following research questions will be addressed using multilevel models controlling for potential individual-level (education, ethnicity, parity, age, Medicaid status) and neighborhood-level (deprivation) confounders: 1) Is a poor neighborhood food environment score, defined as a combination of number of supermarkets, fast food restaurants, fruit and vegetable stands, and natural food stores, associated with higher risk of gestational diabetes?; 2) Does the strength of this association vary according to the mother's education level and employment status?; and 3) What is the association between neighborhood food environment, ethnic concentration and GDM within seven immigrant groups in NYC? Infants of mothers with gestational diabetes are at greater risk of complications at birth including macrosomia and trauma during delivery. They are also at greater risk of obesity, impaired glucose tolerance, and diabetes in childhood and adolescence. Given the increasing incidence of gestational diabetes, along with the ethnic disparity in risk, learning more about contextual risk factors for gestational diabetes is essential for addressing the CDC objectives of promoting healthy pregnancy and birth outcomes and improving risk factors for future disease among infants and toddlers. The proposed study is unique in that it addresses how the neighborhoods in which women live affect their risk of an important complication during pregnancy. Information regarding the associations of neighborhood food environment and ethnic concentration with gestational diabetes can support the design of healthy communities that promote health by encouraging healthy behaviors, quality of life, and social connectedness. [unreadable] [unreadable] [unreadable] [unreadable]